Development of an intrusive core complex and early landsliding on Juana Ridge, Fernandina northwest submarine rift zone, Galápagos Archipelago

Abstract

A ~20-km-long submarine volcanic ridge off the northwestern coast of Fernandina Island, the westernmost of the Galápagos Archipelago, was studied aboard the University of Washington research vessel, the Thomas G. Thompson. The ridge, which I have named Juana Ridge, is a volcanic rift zone formed by movement of magma (magmatic “diking”) in a northwesterly direction from the chamber underlying Fernandina Island. Multiple research methods were employed to determine properties of the seafloor, including sonar mapping to measure bathymetry and reflectivity (high for lava; low for sediment), magnetic field strength measurement and sub-bottom profiling for evidence of sediment cover.